摘要
以锚拉地连墙为支护形式的基坑工程项目为背景,研究了锚固段穿越富水砂加卵石双地层条件下预应力锚索的锚固性能、传力机理、设计计算及优化方法。首先,通过锚索现场拉拔试验发现富水砂加卵石双地层可以提供较好的锚固力,成孔和注浆工效良好。然后,通过调整FLAC^(3D)中的cable单元的浆体粘结力参数逼近现场试验结果,得到锚固段与砂层与卵石层间的极限粘结强度建议值分别为30 kPa和200 kPa;与锚索传力机理理论解析方法相比,FLAC^(3D)中cable单元包含12项参数,可以更加全面地考虑多项影响因素,而且可以反映剪应力峰值随锚固段前端屈服向内部转移的动态过程。最后,通过FLAC^(3D)调整锚固段长度与设置位置达到优化锚索设计的作用。
Based on the background of the foundation pit project supported by the anchored diaphragm wall,the anchorage performance,force transfer mechanism,design calculation and optimization method of the prestressed anchor cable are studied under the condition that the anchorage section of the prestressed anchor cable passes through the water-richsand and pebble two-layer strata.Firstly,pull-out test was carried out,and it was found that the water-rich sand pebble strata can provide reliable anchoring force.The drilling and grouting process also went smoothly.Secondly,by adjusting the grout cohesion of cable element in FLAC^(3D) to approach the field test results,the recommended values of bond strength between anchorage section and sand layer and pebble layer are obtained,which are 30kPa and 200kPa,respectively.Compared with the theoretical analysis of the mechanism of cable force transmission,the cable element in FLAC^(3D) contains 12 parameters,which can consider relative influencing factors more comprehensively.Moreover,it can reflect the dynamic process of the shear stress peak shifting to the inside with the yielding of the front end of the anchoring section.Finally,the anchor cable design is optimized by adjusting the length and position of the anchoring section in FLAC^(3D).
作者
魏支援
王勇
龚晓南
郭盼盼
Wei Zhiyuan;Wang Yong;Gong Xiaonan;Guo Panpan(Research Center of Coastal and Urban Geotechnical Engineering,Zhejiang University,Hangzhou 310058,P.R.China;MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering,Zhejiang University,Hangzhou 310058,P.R.China;CCC Highway Consultants Co.Ltd.,Beijing 100088,P.R.China)
出处
《地下空间与工程学报》
CSCD
北大核心
2021年第5期1507-1516,共10页
Chinese Journal of Underground Space and Engineering
基金
国家自然科学基金(51778575)。
关键词
富水砂加卵石双地层
预应力锚索
拉拔试验
数值模拟
设计优化
water-rich sand and pebble two-layer strata
prestressed anchor cable
pull-out test
numerical simulation
design optimization
